1. Field of the Invention
The present invention relates to coin sorting devices.
2. Description of the Prior Art
In general, as described in Japanese patent application laid-open publication No. 157,085/1980, a coin sorting device includes a coin sorting passage adapted for running a coin or a token on a track between a stationary side plate and a movable side plate opennably connected to and spaced to the stationary side plate. In Japanese patent application publication No. 16/527/1971 there is described a coin sorting device which comprises at least one set of transmitting and receiving coils positioned in alignment with each other at the opposite sides of the coin sorting passage, respectively, for detecting the load impedance of a coin passing between the transmitting and receiving coils to detect the type of material of the coin.
In the known coin sorting device of the type as mentioned above, the coin running track in the coin sorting passage is usually fixed to or integrally formed with the movable side plate hinged to the stationary side plate so that when a coin is stopped in the coin sorting passage due to the coin being deformed, distorted or non-acceptable because it has a diameter larger than that of an acceptable coin, the movable side plate must be moved away from the stationary side plate by operating a return lever or a push button to withdraw the coin running track from the coin sorting passage thereby opening it in a downward direction in order to allow the coin stopped therein to fall into a return chute.
Particularly, in the coin sorting device of the type as mentioned above which comprises a set of transmitting and receiving coils positioned at opposite sides of the coin sorting passage, respectively, so as to detect the load impedance of the coin passing therebetween, the tendency for the coin to stop increases as the sorting accuracy of the coin sorting device is increased. This is because the coils are arranged in predetermined positions corresponding to the specific portion of the coin, such as the peripheral edge or center and therefor the dimension in the vertical direction or the height of the coin sorting passage is restricted to a dimension slightly greater than the diameter of the acceptable coin. These restricted dimensions will prevent the coin from coming out of the predetermined course due to the coin jumping out of the track. Also the distance between the coils is restricted to a dimension slightly greater than the thickness of the acceptable coin to provide high sorting accuracy.
Accordingly, the prior coin sorting devices, discussed above, have serious disadvantages in that the distance between the coils is changed some times because the transmitting coil and the receiving coil are mounted on the stationary side plate and the movable side plate, respectively, so that when the movable side plate is frequently moved away from the stationary side plate to remove a stopped coin from the coin sorting passage between the coils a change in the distance between the coils results. The sorting accuracy of the coin sorting device of the type as mentioned above is greatly affected by changes in the distance between the coils, such that when the standard distance is set to 3.5 mm, a change from the standard distance of 0.25-0.75 mm will result in an impedance difference of 10%.